This week on the blog we take a look at how a top youth swimmer from Hong Kong has learned how making his stroke as long as possible has been detrimental to his swimming. In the process he has shaved off 12 seconds per 100m with less effort to swim with a truly perpetual stroke. Read on to see how he did it...

Tuning Up Harold's Stroke

The next generation of Swim Smooth Certified Coaches are in Perth right now going through some intensive training with Paul Newsome and the rest of the Swim Smooth team.

As part of their studies the coaches have been looking at swimmers of different ability levels to assess how they should swim for maximum speed and efficiency. Last week, one such swimmer flew down to Perth from Hong Kong for a series of training sessions with us - his development over the course of that week makes for an excellent case study:

Harold is a talented 15 year old swimmer who very much fits the "Smooth" Swim Type - moving through the water with a long smooth stroke. However, the interesting thing about his swimming is that he has tried to make his stroke a little too long, dropping his stroke rate (cadence) in the process to try and lengthen things out as much as possible.

Traditional swim coaching has said you should try and swim with as long a stroke as possible but at Swim Smooth we passionately disagree. A long stroke can be a good thing up to a point, it's when it becomes overly long and you add a glide that the problems begin. Actively pausing at the front of the stroke causes you to drop the palm and push forwards on the water.

Here is Harold during his initial filming, pausing at the front of the stroke and dropping the elbow as he does so:

Many swimmers simply slow down when they do this and start to sink in the water. Instead, Harold chooses to kick very hard to push through the dead-spot at the front:

Unfortunately much of the propulsion generated by his kick is wasted in pushing him through the delay and braking effect at the front of his stroke.

In the 1990s some swim coaches went off on a bit of a tangent believing that a longer, slower stroke was more effective. But prior to this way back in 1968, swim coaching god James Counsilman in his book "The Science of Swimming" warned of the dangers of this long-gliding catch-up style and how it was, in fact, less effective:

And here's swimming legend and 5 time Olympic Gold Medallist on the subject:

Note Ian can take as few as 24 strokes in a 50m pool (!) but actually raced at 34 strokes per length - nowhere near the longest stroke he could achieve.

But what about scientific studies? Check out our review here of the 2010 Southwestern University study, showing that energy cost increases when overly-lengthening the stroke, not reducing:

The key chart from the study is this one, showing that as speed is maintained and the stroke rate is reduced (and so the stroke lengthened) oxygen uptake increases:

You may have seen videos of good swimmers / coaches swimming on the spot in a flume tank maintaining the same speed but varying their cadence and purporting to be more efficient when swimming with longer, slower strokes. Don't be fooled into believing what you see here though as what they fail to show in the footage is how strongly they are kicking to maintain this speed (as Harold does) nor can we measure the physiological impact of what this increase in kick has on the cardio vascular system as the 2010 study did. Sure, it looks smooth, but the reality is that the longer, slower stroke comes at a surprisingly high energy cost.

The Southwestern University study above shows just this - as the stroke is lengthened and lengthened, the kicking rate increases and increases. What does this look like in practise? Here's coach Mike (a very smooth swimmer in his own right) demonstrating his normal stroke:

And at the same flume speed he lengthens things out as much as he can. Notice the increase in his kicking rate and how awkward the whole stroke looks:

Tuning Up Harold

Paul and the Swim Smooth coaches first worked on a series of drills and visualisations to remove the pause and brake at the front of Harold's stroke. Then in a follow up session, they put him through his paces during a ramp test, increasing his stroke rate progressively to find where his stroke works most efficiently and effectively - the "sweet spot" of stroke timing.

We filmed this ramp test for you to watch. It takes 24 minutes to complete but it's fascinating viewing to see Harold's stroke timing progressively click into place:

Harold ends up swimming around 12 seconds per 100m faster at his new optimum stroke rate of 66 Strokes Per Minute (SPM) versus his original 50 SPM - all without any increase in perceived effort! This is a HUGE improvement for an already fast swimmer.

Here are the results from the ramp test. Notice the sweet spot at 66 SPM where his stroke is long and fluid, speed is fast and his effort level still remains quite low (6/10):

But how come he can move so much faster without any increase in effort during the test? Firstly because we removed the inefficient pause-and-glide at the front of Harold's stroke making his propulsion much more continuous. And secondly rather than simply pushing him through the dead-spot in his stroke when trying to glide, his kick can now accelerate him forwards with a much more flowing perpetual stroke.

In fact at his new 'sweet spot' of 66 SPM he's moving so quickly now the cameraman is having trouble keeping up:

4 comments:

John a
said...

Hi thereCoinsequently I completed 2 ramp tests this morning. One for my daughter ( a good smooth swimmer and level 3 coach) and one for me (A very average swimmer) My quandary is how to interpret the data. I've drawn graphs etc and am still struggling to identify the 'Sweet Spots.'I am content the tests need doing again and maybe a third time to get some consistent readings. It any advice re interpreting the date more simply would be helpful.

For info my daughters initial SPM was 60 and the data seems to indicate she would be faster going at 57.5 SPM which seems a very slow turnover.Thanks for any tips.

Hi John, you're looking for points where the level of effort is relatively low but the speed is good. Other clues are often where the stroke length is good and/or the stroke looks like it flows visually. Feel free to post numbers for us to look at for you.

Depending on the level of swimmer and their height etc, 57.5 SPM isn't necessarily too slow - for many smooths it's a nice turnover for longer swims.

Also bear in mind that the ramp test works most effectively after a stroke correction session where the new stroke is 'bedding in' a little...

Hi Antony, we didn't measure his ape index but suspect it's quite long (perhaps +3 to +4"). 60 SPM might be right for you - bear in mind that Antony is swimming at a very high level (sub 60 seconds for a 100m) and with that sort of fitness his stroke rate will always be that bit higher.